Italian police have placed seven university lecturers under house arrest as part of a major probe into the alleged rigging of exams.

Fifty-nine people, including a former cabinet minister, are under investigation, while 22 people have been banned from holding academic jobs for 12 months, according to the Italian news agency ANSA.

The investigation started after a group of lecturers tried to persuade a researcher to withdraw from an exam to qualify as a tax lecturer in favour of a less qualified candidate. The researcher who was pressured to withdraw was promised that they would pass in the next exam, according to the news agency. The exam rigging allegedly took place in 2012 and 2013.

Valeria Fedeli, Italy’s education, university and research minister, said that she wanted to “get to the bottom” of the case and in October would launch a code of conduct to help stop corruption and nepotism in Italy’s universities.

The ministry has been working alongside Italy’s anti-corruption authority, the ANAC. Last year, the organisation’s head, Raffaele Cantone, vowed to go after well-connected and corrupt academics known as “barons” in an attempt to improve the image of the country’s academy.

“We are going to tackle this problem head-on and involve the ministry of education, universities and research, university rectors, faculty and students,” he said at the time.